The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Related Articles

Senator Wong noted that both the International Monetary Fund (IMF) and the Reserve Bank of Australia (RBA) had downgraded their forecasts.

"Obviously that has an impact on Australia and on the budget," she said.

Treasurer Wayne Swan has previously warned further savings will be needed to deliver the surplus, with the budget facing declining revenue, an uncertain global economy and falling commodity prices.

In the minutes of its October 2 board meeting released on Tuesday, the RBA said that when it cut the cash rate to 3.25 per cent there was an increased likelihood of domestic economic growth "being somewhat weaker than earlier forecast" over the coming year, particularly due to subdued demand.

The senate inquiry was also told the government was likely to receive another $300 million special dividend from its healthcare provider agency, Medibank Private, in 2012/13.

Medibank managing director George Savvides confirmed the board was considering making its second such dividend payment in three years.

The funds would be drawn from capital reserves as part of the agency's aim of making greater efficiencies, but it would remain comfortably above prudential requirements.

Shadow assistant treasurer Mathias Cormann suggested Medibank was being "extremely helpful" when the government was desperately casting around for cash.

"The last time we spoke about this, a special dividend was supposed to be special," he said.

"Now in three years since Medibank became 'for profit' we have had two special dividends so far, on top of hundreds of millions in ordinary dividends."

Looking beyond the four-year budget estimates period, Mr Tune told the hearing no formal assumptions had been made to fund a National Disability Insurance Scheme (NDIS).

So far, the Labor government has set aside $1 billion to fund the NDIS launch, but any further funding would go beyond 2015/16.

"It depends on what the government does next," Mr Tune said.

"So if the government takes a decision at some subsequent stage after the launch, sites have been evaluated, and decides to go further, then yes, that is the point at which we would say that's firming up, we would book that in."